This proposal outlines a research program consisting of a series of interrelated field experiments in classroom settings and laboratory experiments aimed at assessing the impact that interdependence has on attraction, performance, prejudice reduction, self-esteem and contentment. In the field experiments, children in classrooms will be divided into six-person groups, which will learn normal classroom material through the "jigsaw" process--a technique developed over the past few years in which each student has a part of the information necessary for the understanding of the lesson. This makes each child dependent on the other children. In past studies, we found that such interdependence changed the climate in the classroom. Children became less competitive, less hostile, more cooperative, liked each other more, liked themselves more, liked school more, and even performed better--than children in traditional, more competitive classroom settings. The present proposal extends this research by using the same basic technique (with variations) in an attempt to investigate prejudice reduction, sex-role differentiation, the effects of introducing competition between groups, and other related issues. The program is considered to be important as basic research as well as applied research. It is aimed at increasing our understanding of the effects of cooperation versus competition as well as the development and evaluation of a viable and effective classroom innovation.